Digging wells to access or filter drinking water is a relatively rare behavior in the animal kingdom — only a handful of species have been documented to do so. Researchers from the United Kingdom, Switzerland and Uganda provide the first report of habitual well-digging in a rainforest-living group of East African chimpanzees (Pan troglodytes schweinfurthii); they suggest that this behavior may have been imported into the community’s behavioral repertoire by an immigrant female chimpanzee.
Péter et al. describe the appearance and subsequent spread of well-digging behavior in a previously apparently naïve community of wild East African chimpanzees (Pan troglodytes schweinfurthii). Image credit: Péter et al., doi: 10.1007/s10329-022-00992-4.
“Water, a resource of universal relevance, is rarely considered a concealed resource; it is usually directly accessible from surfaces, cavities, or other types of containers,” said first author Hella Péter, a Ph.D. student in the School of Psychology and Neuroscience at the University of St Andrews and the School of Anthropology and Conservation at the University of Kent, and colleagues.
“However, water is also present beneath the surface, where access is only possible through the creation of wells.”
“Some species have been documented to regularly exploit concealed water. Reports include those on African elephants, warthogs and various equids, such as feral horses and donkeys, khulan, mountain zebras and plains zebra.”
In their research, Péter and co-authors analyzed the behavior of East African chimpanzees in the Waibira community in Uganda.
The well-digging was first observed in Onyofi, a young immigrant female who arrived in 2015 and was immediately very proficient, suggesting she perhaps grew up in a well-digging community.
Since then several other young Waibira chimpanzees and adult females have been seen digging wells.
No adult males were observed digging, however, they regularly use the wells dug by others.
Onyofi’s well-digging attracted a lot of attention from the other chimpanzees in the group, and she was carefully watched both by young chimps and other adults, suggesting that when she arrived the behavior was novel to the Waibira community.
Her wells seem popular, with other chimpanzees drinking from them directly, or using chewed up leaves or moss, demonstrating that there seems to be some added benefit to well-water.
The presence of the behavior also highlights the importance of water as a resource, even for rainforest living populations.
With increasing change in the climate, behavioral adaptations to changes in rainfall may allow groups like Waibira to continue to thrive even when their local habitat starts to change.
“Well digging is usually done to access water in very dry habitats — in chimpanzees, we only know about three savannah living groups who do so,” Péter said.
“What we’ve seen in Waibira is a bit different from those groups. First, they live in a rainforest, so most people assume getting water shouldn’t be a challenge — but it looks like the yearly few months of dry season is enough to cause some trouble for them!”
“What’s also interesting is that the wells all appear next to open water, so the purpose of them is likely filtering, not reaching the water — the chimpanzees might get cleaner or differently flavored water from a well, which is fascinating.”
“One of the most interesting things was seeing the other chimpanzees’ responses to Onyofi’s digging — even large dominant males would politely wait for her to finish digging and drinking, and only then go and borrow her well, which is pretty unusual around such a valuable resource,” said senior author Dr. Catherine Hobaiter, a researcher in the School of Psychology and Neuroscience at the University of St Andrews and the Budongo Conservation Field Station.
“We’re curious to see what happens once some of the young males who can dig grow older — maybe they will be acceptable teachers for the big males, and they’ll stop relying on others to dig wells for them.”
The study was published in the journal Primates.
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H. Péter et al. Well-digging in a community of forest-living wild East African chimpanzees (Pan troglodytes schweinfurthii). Primates, published online June 6, 2022; doi: 10.1007/s10329-022-00992-4
Source link: https://www.sci.news/biology/well-digging-chimpanzees-10947.html
